Stone mosaics have been desirable decorative art since pre-Roman times. Traditionally, stone mosaics are made from assembling small tesserae made by cutting colored glass, stone or other materials into square or triangular pieces. As the aesthetics of mosaics decoration develops, consumers now prefer stone mosaics with intricate patterns and inlay configuration. FIG. 1A shows a mosaic pattern surface of this type. As further shown in FIG. 1B, the mosaic pattern surface is usually composed of a repetition of a plurality of repeating units 1 arranged one adjacent another. Each repeating unit 1 is in turn composed of one or more tesserae 11, 12, 13, 14, 15 and 16 of different materials, shapes, colors, patterns or textures. Some tesserae 14, 15 and 16 can be inlaid within others 11, 12 and 13. A tessera is the basic unit forming the mosaic pattern surface.
Presently, there are no economic methods for efficient mass production of these basic units of stone mosaics with intricate patterns. While tesserae 14, 15 and 16 may be produced by methods such as grinding, the same methods do not apply to the production of tesserae 11, 12 and 13, as they have internal openings that must be formed by cutting. Waterjet cutting technology is commonly used to cut the tesserae with internal openings or inside cuts. However, the process is expensive and labor intensive. Each tessera has to be cut from a stone plate of a desired thickness by waterjet machines, and then glued by hand to form the repeating unit. Adding to the already high cost of waterjet cutting is the labor cost to compose the tesserae into repeating units. There are also difficulties in the precision of the cutting. A tessera may either be too big to fit into a repeating unit, or too small resulting in visible seams, slits or gaps between adjacent tesserae in a repeating unit, as shown in FIG. 1B. A need therefore exists for a method of producing tesserae or repeating units of a mosaic pattern surface that eliminates or diminishes at least some of the disadvantages and problems described above.